Fourier transform infrared chemical composition analysis

The thermal characterisation of elastomers has recently been reviewed by Sircar [28] from which it appears that DSC followed by TG/DTG are the most popular thermal analysis techniques for elastomer applications. The TG/differential thermal gravimetry (DTG) method remains the method of choice for compositional analysis of uncured and cured elastomer compounds. Sircar s comprehensive review [28] was based on single thermal methods (TG, DSC, differential thermal analysis (DTA), thermomechanical analysis (TMA), DMA) and excluded combined (TG-DSC, TG-DTA) and simultaneous (TG-fourier transform infrared (TG-FTIR), TG-mass spectroscopy (TG-MS)) techniques. In this chapter the emphasis is on those multiple and hyphenated thermogravimetric analysis techniques which have had an impact on the characterisation of elastomers. The review is based mainly on Chemical Abstracts records corresponding to the keywords elastomers, thermogravimetry, differential scanning calorimetry, differential thermal analysis, infrared and mass spectrometry over the period 1979-1999. Table 1.1 contains the references to the various combined techniques. 

The apparatus used for IR microscopy is a Fourier-transform infrared (FTIR) spectrometer coupled on-line with an optical microscope. The microscope serves to observe the sample in white light at significant magnification for the purpose of determining its morphology, as well as to select the area for analysis. The spectrometer, on the other hand, enables study of the sample by transmission or reflection measurement for the purpose of determining the chemical composition. It also provides information about the microstructure and optical properties (orientation) of the sample. It is possible to apply polarised light both in the observation of the sample and in spectrometric measurements. 

Characterization of catalysts The zeolite structure was checked by X-ray diffraction patterns recorded on a CGR Theta 60 instrument using Cu Ka, filtered radiation. The chemical composition of the catalysts was determined by atomic absorption analysis after dissolution of the sample (SCA-CNRS, Solaize, France). Micropore volumes were measured by N2 adsorption at 77 K using a Micromeritics ASAP 2000 apparatus and by adsorption of cyclohexane (at P/Po=0.15) using a microbalance apparatus SET ARAM SF 85. Incorporation of tetrahedral cobalt (II) in the framework of Co-Al-BEA and Co-B-BEA was confirmed by electronic spectroscopy [18] using a Perkin Elmer Lambda 14 UV-visible diffuse reflectance spectrophotometer. Acidity measurements were performed by Fourier transform infrared spectroscopy (FT-IR, Nicolet FTIR 320) after pyridine adsorption. Self-supported wafer of pure zeolite (20 mg/cm ) was outgassed at 673 K for 6 hours at a pressure of lO Pa. After cooling at 423 K, the zeolite was saturated with pyridine vapour (30 kPa) for 5 min, evacuated at this temperature for 30 min and the IR spectrum was recorded. 

Raman microspectroscopy is the fastest and most powerful tool for analysis of phase transformations in contact loading. It can additionally provide information on residual stresses and/or chemical changes in the surface layers. However, limited databases of Raman spectra and difficulties with the interpretation of Raman spectra, as well as low accuracy of existing predictive tools for calculations of Raman spectra of solids, make it necessary to complement Raman data with electron or X-ray diffraction studies. Fourier-transform infrared microspectroscopy is another technique that can provide useful information on structural and compositional changes in the surface layer. 

The chemical polymerization of Py by CAN in PU solutions leads to the formation of PU/PPy composites. The composites were characterized by Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR], dynamic mechanical analysis (DMA], thermal gravimetric analysis (TGA], differential scanning calorimetry (DSC], X-ray photoelectron spectroscopy (XPS], and SEM measurements. The absorbances of the disordered H-bonded urethane carbonyl decrease with increasing Py concentration. The fraction of the hydrogen-bonded carbonyls is increased and the melting point increases with the increase of PPy content. These indicate the incorporation of PPy into PU may cause the complex due to the intermolecular interaction between the PPy and PU. SEM images of composite nanofibers show good distribution of the second component and the composite solution is proper to form conductive composite nanofibers. 

Fourier transform infrared (FTIR) spectra of the 3% CP, 6% CP, and 9% CP composites were recorded on a Bruker Tensor 27 single-beam instrument at 16 scans with a nominal resolution of 4cm Absorption spectra were saved from 4000 to 700cm . The FTIR analysis was conducted in order to better understand the nature of interactions between the two polymers. As discussed previously, it is expected that the interaction between the CP molecules and the PSMP molecules should be physical instead of chemical, which can be validated by FTIR spectra. 

Thermogravimetric analyzers may be connected to a variety of chemical analyzers to determine the exact composition ofthe outgassed materials as they are evolved. Among chemical analysis methods are gas chromatography, infrared spectroscopy, and mass spectroscopy for example, a TGA apparatus may be coupled with a Fourier Transform Infrared (FTIR) spectrophotometer to measure the thermal oxidative stabilities of several fluorinated polyimides. 

Chemical characterization of the UHMWPE powder is typically performed at the powder-manufacturing site as part of their quality control protocol. However, researchers may want to periodically verify the purity and composition of the powder. ASTM 648 outlines several tests that can be used to analyze the powder. With regards to chemical characterization, trace element analysis and Fourier transform infrared spectroscopy (FTIR) are the two common approaches. 

Qian et al. conducted a study on bamboo particles (BP) that were treated with low-concentrations of alkali solution for various times and used as reinforcements in PLA based composites [35]. Characteristics of BP by composition analysis, scaiming electron microscopy, Brunauer-Emmett Teller test, and Fourier transform infrared spectroscopy, showed that low-concentration alkali treatment had a significant influence on the microstructure, specific surface area, and chemical groups of BP. PLA/treated-BP and PLA/untreated-BP composites were both produced with 30 wt% BP content. Mechanical measurements showed that tensile strength, tensile modulus, and elongation at break of PLA/BP composites increased when the alkali treatment time reached... 

Most utility polymeric articles available today contain multiphase polymeric systems comprised of semi-crystalline polymers, copolymers, polymers in solution with low molar mass compounds, physical laminates or blends. The primary aim of using multicomponent systems is to mould the properties available from a single polymer to another set of desirable material properties. The property development process is complex and depends not only on the properties of the polymer(s) and other components but also on the formation process of the system which determines the developed microstmcture, and component interaction after formation. Moreover, the process of polymer composite formation and the stability of the composite is a function of environmental parameters, e.g., temperature, presence of other species etc. The chemical composition and some insight into the microscopic structure of constituents in a polymer composite can be directly obtained using Infrared (IR) spectroscopy. In addition, a variety of instrumental and sampling configurations for spectroscopic measurements combine to make irrfra-red spectroscopy a versatile characterization technique for the analysis of the formation processes of polymeric systems, their local structure and/or dynamics to relate to property development under different environmental conditions. In particular, Fourier transform infrared (FTIR) spectroscopy is a well-established technique to characterize polymers [1, 2]. 

For chemical composition analysis Fourier transform infrared (FTIR) or even Raman spectrometry are used. 

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